This invention relates to heaters, in particular to heaters for heating the coolant of vehicles and to burner head assemblies and control modules therefor.
Fuel-powered vehicle heaters are used for two main purposes. The first purpose is to heat the coolant of the vehicle so the vehicle is easier to start in cold climates. This is particularly important for diesel-powered vehicles which are often difficult to start due to low volatility of the fuel. However these heaters have a second important function, particularly for transit vehicles such as buses. Heaters relying solely on the engine coolant as heated by the engine may be insufficient to provide a comfortable interior temperature. Accordingly, fuel-powered heaters may be used to supplement the heat by providing additional heat to the coolant.
Fuel-powered vehicle heaters conventionally include a combustion chamber surrounded by a coolant jacket where the coolant is heated by combustion of fuel in the combustion chamber. There is a burner head assembly connected to the combustion chamber which includes such components as a combustion fan, an electric motor for the fan, a burner, a compressor for supplying compressed air to the burner and a control module. In some prior art heaters the control module is mounted as an exterior unit on the burner head assembly. In such units there are wiring harnesses which connect the control module to the components within the burner head assembly. At least one aperture in the burner head assembly is required to connect the control module to components inside or outside of the burner head assembly.
Prior art vehicle heaters conventionally have a fixed location for connecting wiring harnesses to the heater. This may provide difficulties with some installations since in different vehicles wiring may be coming from different directions towards the location of the heater.
Conventional vehicle heaters are usually provided with air filters for filtering air for the compressor of the heater. These air filters should be in a location where they can be conveniently changed when required. This sometimes requires an exterior housing for the air filter and/or hoses connecting the air filter to the compressor. These features can complicate the design and make the overall package less efficient.
Accordingly it is an object of the invention to provide an improved vehicle heater, and burner head assembly and control module for such a heater, where exterior and interior wiring can be connected to a control module without requiring wiring harnesses passing through the wall of the burner head assembly itself.
It is also an object of the invention to provide an improved vehicle heater, and burner head assembly and control module for such a heater, where the control module forms part of the body of the heater such that no irregular shapes or additional grommets or seals are required.
It is a further object of the invention to provide an improved vehicle heater, and burner head assembly and control module for such a heater, where sealing between the control module and the burner head assembly can be accomplished without the need for separate O-rings or seals.
It is a still further object of the invention to provide an improved vehicle heater, and burner head assembly and control module for such a heater, where the housing for the burner head assembly includes mounts for an air filter as well as an air conduit extending to the compressor, without the need for additional fittings, hoses or clamps.
It is a still further object of the invention to provide an improved vehicle heater, and burner head assembly and control module for such a heater, where the control module can be moved relative to the housing for the burner head assembly, thereby moving exterior electrical connectors to alternative locations on the heater.